Systems and methods for positioning a hoist and hook

ABSTRACT

Systems and methods for operating a hoist and hook assembly may determine a position of a target using a position sensor. A hook assembly may be positioned in response to the position of the target as detected by the position sensor. Positioning the hook assembly may include articulating a boom coupled to a hoist, using one or more local thrust sources on the hook assembly, and/or moving an airframe relative to the position of the target.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a nonprovisional of, and claims priority to, and thebenefit of U.S. Provisional Application No. 62/320,112 entitled “SYSTEMSAND METHODS FOR POSITIONING A HOIST AND HOOK” and filed on Apr. 8, 2016,which is hereby incorporated by reference in its entirety.

FIELD

The disclosure relates generally to hoist and hook assemblies for movingloads, and more particularly, to systems and methods for positioninghoists and/or hooks.

BACKGROUND

Hoists may be used to apply pulling force through a cable or otherlifting medium to a load. Hoists and hooks are used in various verticalapplications including, for example, cranes and aircraft mounted rescuehoists. Hoists may typically have a hook at the end of a cable that isattachable to the load. During operation, a hook may be lowered anddirected to a target to retrieve an item or may be lowered toward atarget and released to emplace a load at a target location. Moving thehook to a target may involve manual processes such as a pilot moving thehelicopter from which the hoist is being operated.

Rescue conditions and other hoist operation at sea may include tidalvariations and uneven sea levels associated with waves. A target in suchan operation may be moving in a complex fashion in response to theundulating sea surface.

Furthermore, the hook at the end of a cable may move with a delayrelative to the motion of the hoist at the top of the cable or thestructure to which the hoist is attached. Thus, a pilot may move ahelicopter, for example, in an attempt to deliver the hook to a targetonly for the target to shift before the hook is positioned.

SUMMARY

A hoist and hook system is provided. The system includes a hoist, acable coupled to the hoist, and a hook assembly coupled to the cable.The hook assembly may also include a position sensor configured todetect a position of a target.

In various embodiments, the system may include a communication device inelectronic communication with the position sensor. A boom may be coupledto the hoist and configured to articulate in response to the position ofthe target. One or more local thrust source may be coupled to the hookassembly. An airframe may be coupled to the boom or hoist. The airframemay be configured to reposition in response to the position of thetarget. The hook assembly may further comprise a compass configured todetect a rotational orientation of the hook assembly. A tracking systemmay be in communication with the position sensor.

A method of operating a hoist and hook assembly is also provided. Themethod may include the steps of determining a position of a target usinga position sensor, positioning a hook assembly in response to theposition of the target. The system may deliver the hook assembly to thetarget.

In various embodiments, the position of the target may be determined inreal-time. The position of the target may also be a future positionprojected based on a real-time position of the target and/or a pastposition of the target. The real-time position data may be captured andprocessed at a rate sufficient to maintain stability of a control systemthat uses the input data for a control process. A controller may projecta future position of an airframe coupled to the boom or hoist.Positioning the hook assembly may include repositioning the airframe inresponse to the position and/or predicted position of the target.Positioning the hook assembly may also include instructing one or morelocal thrust sources to position the hook assembly. Positioning the hookassembly may further comprise articulating a boom coupled to the hoistassembly to reposition the hoist assembly.

An article of manufacture is also provided. The article may include anon-transitory, tangible computer readable storage medium havinginstructions stored thereon that, in response to execution by aprocessor, cause the processor to perform operations. The operations mayinclude determining a real-time position of a target using a positionsensor, positioning a hook assembly coupled to a hoist assembly by acable at least partially in response to the real-time position of thetarget, and delivering the hook assembly to the target.

In various embodiments, the operations may include positioning the hookassembly at least partially in response to a future position of thetarget projected using a model based at least partially on the real-timeposition of the target. The operations may also include projecting afuture position of an airframe coupled to the boom or hoist assembly,and positioning the hook assembly at least partially in response to thefuture position of the airframe. The operations may further includeprojecting a future position of the hook assembly and positioning thehook assembly at least partially in response to the length andcharacteristics such as linear mass and stiffness of the deployed cable.Positioning the hook assembly may further include instructing one ormore local thrust sources to position the hook assembly and/orarticulating a boom coupled to the hoist assembly to reposition thehoist assembly. The operations may also include tracking the targetusing a tracking system based on at least one of Cartesian coordinates,polar coordinates, spherical coordinates, or cylindrical coordinates.

The forgoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosures, however, maybest be obtained by referring to the detailed description and claimswhen considered in connection with the drawing figures, wherein likenumerals denote like elements.

FIG. 1 illustrates an exemplary hoist assembly and hook assemblymechanically coupled to an aircraft for positioning the hoist assemblyand/or hook assembly, in accordance with various embodiments;

FIG. 2 illustrates a hook assembly having a sensor configured to detectthe position of a target, in accordance with various embodiments;

FIG. 3 illustrates an exemplary position map of a target relative to areference point such as an airframe, a hoist, or a hook, in accordancewith various embodiments;

FIG. 4 illustrates an exemplary system for positioning a hoist assemblyand/or a hook assembly using an articulating arm or boom, in accordancewith various embodiments;

FIG. 5 illustrates an exemplary system for positioning a hook assemblyusing one or more local thrust sources, in accordance with variousembodiments;

FIG. 6 illustrates an exemplary method for delivering a hook assembly toa target using a detected position of a target, in accordance withvarious embodiments; and

FIG. 7 illustrates an exemplary method for delivering a hook assembly toa target using a projected position of a target, in accordance withvarious embodiments.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration and their best mode. While these exemplary embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the disclosures, it should be understood that other embodimentsmay be realized and that logical, electronic, and mechanical changes maybe made without departing from the spirit and scope of the disclosures.Thus, the detailed description herein is presented for purposes ofillustration only and not of limitation. For example, the steps recitedin any of the method or process descriptions may be executed in anyorder and are not necessarily limited to the order presented.Furthermore, any reference to singular includes plural embodiments, andany reference to more than one component or step may include a singularembodiment or step. Also, any reference to attached, fixed, connected orthe like may include permanent, removable, temporary, partial, fulland/or any other possible attachment option. Additionally, any referenceto without contact (or similar phrases) may also include reduced contactor minimal contact.

Hoist and hook systems of the present disclosure may position a hoistassembly and/or a hook assembly based on the detected and/or projectedposition of a target. The terms position and location may be used hereininterchangeably. A target may be identified using an electromagnetic oracoustic sensor mechanically coupled to the hoist assembly and/or hookassembly. The target's position may then be tracked and/or projectedrelative to the perspective of the hoist assembly, hook assembly, and/orstructure to which the hoist is mounted. The hoist assembly and/or hookassembly may then be positioned based on the position and/or projectedposition of the target to deliver the hook assembly to the target.

In various embodiments, one or more electromagnetic or acoustic sensorsmay be mechanically mounted on the airframe and/or on detachedstructures such as deployed buoys, fixed buoys, other aircraft, nearbyships, and the like, provided that the one or more sensors mayindividually or collectively provide equivalent information such thatthe relative position of the target from the hoist assembly, hookassembly, or airframe may be computed. Such detached or displacedsensors may be especially useful when the view of the target from thehoist assembly is obscured as may happen with a sling load.

Referring now to FIG. 1, an exemplary hoist and hook system 100 isshown, in accordance with various embodiments. Hoist and hook system 100includes an airframe 102 mechanically coupled to a hoist assembly 104.Hoist assembly 104 may be coupled directly to airframe 102 ormechanically coupled to a boom that is mechanically coupled to airframe102. Cable 106 may be wound about a drum within hoist assembly 104 andreleased or retracted based on rotation of the drum. Cable 106 may thushang at various distances from hoist assembly 104 and airframe 102. Ahook assembly 108 may be coupled to cable 106 at the free end of thecable opposite hoist assembly 104. Hook assembly 108 may hang from hoistassembly 104 on cable 106. Cable 106 and hoist assembly 104 may thusswing and/or translate relative to hoist assembly 104 and airframe 102.The position of hoist assembly 104 may be controlled in part by changingthe position of hoist assembly 104 and/or airframe 102.

Referring now to FIG. 2, hook assembly 108 is shown coupled to an end ofcable 106, in accordance with various embodiments. Hook assembly 108 maybe configured to detect the position of a target. Hook assembly 108 mayinclude body 200. Hook interface 202 may extend from body 200 oppositecable 106. Hook interface 202 may be configured for attachment to a loadto hoist the load on cable 106. Hook interface 202 may be manuallyoperable or may be remotely operable to facilitate engagement anddisengagement without manual assistance at the target site. Hookassembly 108 may further include systems such as a compass 204, aposition sensor 206, and/or a communication device 208.

In various embodiments, hook assembly 108 may rotate on cable 106relative to airframe 102 and/or hoist assembly 104 of FIG. 1 about thevertical axis (i.e., the z axis in FIG. 1). Compass 204 may be anelectromagnetic compass configured to determine the orientation of hookassembly 108 relative to the cardinal directions. The relative positionof hook assembly 108 detected by compass 204 may be compared to the arelative position of airframe 102 and/or hoist assembly 104 relative tothe cardinal directions as detected by a similar compass. Thus, compass204 may be used to determine the orientation of hook assembly 108relative to airframe 102 and/or hoist assembly 104. Compass 204 may alsobe an electronic device configured to detect an orientation of hookassembly 108 relative to airframe 102 and/or hoist assembly 104 of FIG.1 such as, for example, a beacon system comprising two or more beaconson hook assembly 108 or detectable fiducial marks that are used todetermine the rotational orientation of hook assembly 108 about cable106.

In various embodiments, position sensor 206 may comprise a variety ofposition sensing devices including passive and/or active sensors. Forexample, position sensor 206 may be an optical position sensor capableof detecting visible light such as, for example, an imaging device orcamera. The visible light may be captured in still frame images or videofor use in identifying a target, detecting a target's position, and/orprojecting a target's future position. In that regard, position sensor206 may be configured to detect a target without the presence of abeacon on the target. Position sensor 206 may also detect otherspectrums of electromagnetic radiation or acoustic pressure waves suchas radio, infrared, ultraviolet, ultrasonic, or the like.

In various embodiments, position sensor 206 may additionally be adistance, range, and/or depth sensing device. Such a distance, range, ordepth sensor may be operable in the electromagnetic or acoustic spectrumcapable of producing a depth map (also known as a point cloud oroccupancy grid). Various distance, range, or depth sensing sensortechnologies and devices include, but are not limited to, a structuredlight measurement, phase shift measurement, time of flight measurement,stereo triangulation device, sheet of light triangulation device, lightfield cameras, coded aperture camera, computational imaging techniques,simultaneous localization and mapping (SLAM), imaging radar, imagingsonar, laser radar, scanning LIDAR, flash LIDAR, or a combinationcomprising at least one of the foregoing. Different technologies caninclude active (transmitting and receiving a signal) or passive (onlyreceiving a signal) and may operate in a band of the electromagnetic oracoustic spectrum such as visual, infrared, ultrasonic, etc.

In various embodiments, a beacon may be placed on a target to transmitthe position of the target to position sensor 206 for position sensor206 configured to operate on, for example, radio frequencies ofelectromagnetic radiation. In various embodiments, fiducial marks mayhave been placed on a target to improve the accuracy of its detection byposition sensor 206. Position sensor 206 may be fixedly coupled to hookassembly 108, hoist assembly 104, and/or airframe 102 to detect aposition of a target relative to the hook assembly 108, hoist assembly104, or airframe 102, respectively.

In various embodiments, communication device 208 may be in electroniccommunication with compass 204 and/or position sensor 206. Communicationdevice 208 may be, for example, a wireless transceiver. Communicationdevice 208 may be configured to transmit and/or receive data to and/orfrom hook assembly 108. In that regard, communication device 208 maytransmit data captured by compass 204 and/or position sensor 206.Communication device 208 may be in electromagnetic communication with asimilar communication device on airframe 102 and/or hoist assembly 104.In various embodiments, cable 106 may also be configured to carryelectrical power and/or electrical signals between hook assembly 108 andhoist assembly 104.

With reference to FIG. 3, an exemplary tracking system 300 is shown, inaccordance with various embodiments. Tracking system 300 may implement aCartesian coordinate system as illustrated with a point 306 located atan intersection between a vertical axis 304 and a horizontal axis 302that is orthogonal to the vertical axis 304. Although a Cartesiancoordinate system is illustrated for tracking system 300, othercoordinate systems such as a polar coordinate system, a cylindricalcoordinate system, a cubic coordinate system, and/or a sphericalcoordinate system may be employed by tracking system 300. In thatregard, the tracking system may implement a 2-dimensional coordinatesystem as illustrated or a 3-dimensional coordinate system.

Tracking system 300 may identify the position of target 308 relative topoint 306. Point 306 may represent the location of a reference pointsuch as, for example, a location of a position sensor 206 on at leastone of airframe 102, hoist assembly 104, and/or hook assembly 108 ofFIG. 1 in the x-y plane. In that regard, the orientation of horizontalaxis 302 and vertical axis 304 may be fixed relative to at least one ofairframe 102, hoist assembly 104, and/or hook assembly 108. Verticalaxis 304 may, for example, extend from aft to forward along airframe 102and horizontal axis 302 may extend across airframe 102 perpendicular tovertical axis 304. Tracking system 300 may also include a depth of thetarget in a Z direction. The depth may be measured, for example, by aposition sensor 206 and/or a length of cable 106 deployed from hoistassembly 104.

For example, tracking system 300 may determine that target 308 isdistance 310 from the horizontal axis 302 and distance 312 from thevertical axis 304. The distances may include positive and negativenumbers to indicate which side of point 306 the distances lie on theirrespective axis. The position of target 308 relative to point 306 (i.e.,airframe 102, hoist assembly 104, and/or hook assembly 108) may thus berepresented by an ordered pair (representing coordinates along thehorizontal and vertical axis) or 3-tuple (adding a third coordinate forthe z-direction). The relative position of target 308 may be used toissue movement commands to airframe 102, hoist assembly 104, and/orairframe 102 to align hook assembly 108 relative to target 308.

Tracking system 300 may be operated by and executed on a controller. Acontroller may be, for example, a computer based-system having aprocessor and memory. A controller may thus include one or moreprocessors and one or more tangible, non-transitory memories and becapable of implementing logic. The processor can be a general purposeprocessor, a digital signal processor (DSP), an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA), agraphical processing unit (GPU), or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof.

In various embodiments, the processor may thus be configured toimplement various logical operations in response to execution ofinstructions, for example, instructions stored on a non-transitory,tangible, computer-readable medium. As used herein, the term“non-transitory” is to be understood to remove only propagatingtransitory signals per se from the claim scope and does not relinquishrights to all standard computer-readable media that are not onlypropagating transitory signals per se. Stated another way, the meaningof the term “non-transitory computer-readable medium” and“non-transitory computer-readable storage medium” should be construed toexclude only those types of transitory computer-readable media whichwere found in In Re Nuijten to fall outside the scope of patentablesubject matter under 35 U.S.C. § 101.

In various embodiments, the controller may be in electroniccommunication with a position sensor 206 (of FIG. 2). The controllermay, for example, receive a signal from position sensor 206 encoding theposition of target 308 (of FIG. 3) relative to point 306 (of FIG. 3).The controller and position sensor 206 may be in electroniccommunication via, for example, one or more of a wire, a bus, a circuit,a wireless channel, or another suitable electronic communicationchannel. The controller may transmit control signals to airframe 102,hoist assembly 104, and/or hook assembly 108 of FIG. 1.

Referring now to FIG. 4, a perspective view of hoist and hook system 100having a boom 404 capable of articulation is shown, in accordance withvarious embodiments. Boom 404 may be coupled to airframe 102 at mountingpoint 400. One or more actuators 402 may be configured to position hoistassembly 104 and/or hook assembly 108 in the x-y plane by articulationof boom 404. The length of cable 106 deployed to hook assembly 108controls the distance of the hook assembly from airframe 102substantially in the z-direction.

Referring briefly to FIGS. 3 and 4, tracking system 300 may be used todetermine the desired position of hoist assembly 104 and/or hookassembly 108 relative to target 308. For example, tracking system 300may indicate that boom 404 should be actuated distance 310 in the xdirection and distance 312 in they direction to align hook assembly 108with target 308 in the x-y plane. Similarly, tracking system 300 mayindicate that airframe 102 should move distance 310 in the x directionand distance 312 in the y direction to align hook assembly 108 withtarget 308 in the x-y plane.

With reference to FIG. 5, a hook assembly 108 having one or more localthrust sources 500 is shown, in accordance with various embodiments.Hook assembly 108 may translate in the z direction in response to cable106 being deployed or retracted and/or movement of airframe 102 in the zdirection. Compass 204, position sensor 206, and communication device208 may be used to identify the position of hook assembly 108 relativeto target 308 of FIG. 3. The local thrust sources 500 may be coupled tobody 200 of hook assembly 108. The local thrust sources 500 may beconfigured to translate or rotate hook assembly 108 in the x-y plane.The local thrust sources 500, and/or cable 106, and/or airframe 102 mayalso be configured to translate hook assembly 108 in the z direction.The one or more local thrust sources 500 may be, for example,electronically powered propellers configured to generate thrust inresponse to rotation.

Referring briefly to FIGS. 3 and 5, tracking system 300 may be used todetermine the desired position of hook assembly 108 relative to target308. For example, tracking system 300 may indicate that hook assembly108 should translate distance 310 in the x direction and distance 312 inthey direction to align hook assembly 108 with target 308 in the x-yplane. The translation of hook assembly 108 may thus direct hookinterface 202 to target 308.

Referring now to FIG. 6, an exemplary process 600 for delivering a hookto a target is shown using hoist and hook system 100 of FIG. 1 andtracking system 300 of FIG. 3 controlled by a computer-based controller,in accordance with various embodiments. The controller may detect aposition of a target 308 (Step 602). As described above with referenceto FIGS. 2 and 3, the position of target 308 may be detected usingtracking system 300 and a position sensor 206. The position may be aposition of the target relative to a point such as a hook assembly,hoist assembly, or airframe.

In various embodiments, the controller may position a hook assembly 108in response to the position of the target (Step 604). The position ofthe target may be detected by the controller via electroniccommunication with position sensor 206 using tracking system 300. Theposition may be identified using a coordinate system and/or a set ofmovement commands. The position may also be a current position asmeasured by position sensor 206.

In various embodiments, the controller may then deliver hook assembly108 to a target (Step 606). The hook assembly may be delivered bytransmitting movement commands to an autopilot configured to repositionairframe 102, to the local thrust sources 500 to position hook assembly108, and/or to boom 404 to position hoist assembly 104. In that regard,airframe 102, hoist assembly 104, and/or hook assembly 108 may bepositioned in response to the position of a target 308.

Referring now to FIG. 7, an exemplary process 700 for delivering a hookassembly 108 (of FIG. 1) to a target 308 (of FIG. 3) using a projectedposition of the target is shown, in accordance with various embodiments.The system may be controlled by a computer-based controller as discussedwith reference to FIGS. 3 and 6 above. The controller may project afuture position of the target (Step 702). The future position may beprojected by detecting and logging positions of the target in real-time.Future positions may be modeled based on previous and/or currentpositions using modeling or filtering methods such as a Bayesian filter.Suitable Bayesian filters for short-term prediction include Kalmanfilters and Particle filters. Other motion models, especially those thatexplicitly include uncertainty of estimated target position, may beused. For instance, the future position of hook assembly 108 may bepredicted, in part, on a model of the dynamics of cable 106. Such amodel might include the deployed length of cable 106 and characteristicssuch as linear mass and stiffness of cable 106. Based on the predictedmotion of the target and/or hook assembly 108, model-predictive controlmethods may be used to account for changing behavior of hook assembly108 and/or target 308.

The controller may also project a future position of the aircraft (Step704). The future position of the aircraft may be projected independentlybased on airspeed, past positions, and/or current positions of theaircraft. The future position of the aircraft may also be indirectlyprojected along with the position of the target, since the position ofthe target may be projected using a position sensor 206 coupled toairframe 102.

In various embodiments, the controller may position hook assembly 108 inresponse to the projected position of the target and/or the projectedposition of the aircraft (Step 706). The controller may position hookassembly 108 directly or indirectly by transmitting movement commands toan autopilot configured to reposition airframe 102, to the one or morelocal thrust sources 500 to position hook assembly 108, and/or to boom404 to position hoist assembly 104. The controller may thus deliver thehook assembly 108 to target 308 (Step 708).

Systems and methods of the present disclosure tend to reduce the time toposition the hoist free-end (i.e., hook assembly 108), reduceoperational risk, and increase the probability of success for rescueoperations. Sensors may help to pinpoint the location of a person inneed of rescue and/or more precisely place a suspended load. The sensedlocation may be used to position the various components of hoist andhook system 100.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosures.

The scope of the disclosures is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” Moreover, where a phrase similar to“at least one of A, B, or C” is used in the claims, it is intended thatthe phrase be interpreted to mean that A alone may be present in anembodiment, B alone may be present in an embodiment, C alone may bepresent in an embodiment, or that any combination of the elements A, Band C may be present in a single embodiment; for example, A and B, A andC, B and C, or A and B and C. Different cross-hatching is usedthroughout the figures to denote different parts but not necessarily todenote the same or different materials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”, “anexample embodiment”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is to be construed under theprovisions of 35 U.S.C. 112(f), unless the element is expressly recitedusing the phrase “means for.” As used herein, the terms “comprises”,“comprising”, or any other variation thereof, are intended to cover anon-exclusive inclusion, such that a process, method, article, orapparatus that comprises a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus.

What is claimed is:
 1. A hoist and hook system, comprising: a hoist; acable coupled to the hoist; a hook assembly coupled to the cable; aposition sensor disposed on one of the hoist or the hook assembly andconfigured to detect a position of a target, located remote from theposition sensor, relative to at least one of the hoist or the hookassembly; and a compass disposed on the hook assembly and configured todetermine an orientation of the hook assembly relative to the hoist. 2.The hoist and hook system of claim 1, further comprising a communicationdevice in electronic communication with the position sensor.
 3. Thehoist and hook system of claim 1, further comprising a boom coupled tothe hoist, wherein the boom is configured to articulate in response tothe position of the target.
 4. The hoist and hook system of claim 1,further comprising a local thrust source coupled to the hook assembly.5. The hoist and hook system of claim 1, further comprising an airframecoupled to at least one of the hoist or a boom coupled to the hoist,wherein the airframe is configured to reposition in response to theposition of the target.
 6. The hoist and hook system of claim 1, furthercomprising a tracking system in communication with the position sensor,wherein the tracking system is configured to calculate a relativeposition of the target and at least one of the hoist and the hookassembly.